Lasse Riemann

Title of Lasse's keynote is: Heterotrophic N2 fixation in the oceans

Biological dinitrogen (N2) fixation is performed solely by specialized prokaryotes termed diazotrophs, introducing new reactive nitrogen into aquatic environments. Conventionally, cyanobacteria are here considered the major diazotrophs. However, accumulating evidence indicates that diverse non-cyanobacterial diazotrophs (NCDs) inhabit a wide range of aquatic ecosystems, including temperate and polar latitudes, coastal environments and the deep ocean. In this talk, I will review our efforts to decipher the importance and ecology of marine NCDs, with particular focus on their particle-associated lifestyle and on coastal waters.